Das J R, Bhakoo M, Jones M V, Gilbert P
Unilever Research, Port Sunlight Laboratory, Wirral, UK.
J Appl Microbiol. 1998 May;84(5):852-8. doi: 10.1046/j.1365-2672.1998.00422.x.
Differences in opacity between wells of a microtitre plate containing different volumes of inoculated growth medium reflected planktonic growth without any contribution from cells attached at the well surface. Simple algebra and a knowledge of the dependence of optical density upon sample path length (volume) for suspensions of differing cell density enables the generation of growth curves for attached populations (biofilms). In this manner, minimum inhibitory concentrations (MICs) were determined at various stages of growth (0-20 h), both for cells growing attached to the bases of the plate wells and, simultaneously, for cells growing in suspension above them. Biocides included cetrimide, polyhexamethylene biguanide, peracetic acid, phenoxyethanol and chloroxylenol. Results, expressed as planktonic:biofilm MIC ratios, showed susceptibility to change, not only as a function of attachment and biofilm formation, but also with respect to the nature of the chemical agent. In some instances, changes in susceptibility greater than twofold occurred immediately on attachment and could occur in the presence of biocide concentrations which exceeded the MIC.
含有不同体积接种生长培养基的微量滴定板各孔之间的浊度差异反映了浮游生长情况，没有来自孔表面附着细胞的任何影响。简单的代数运算以及对不同细胞密度悬浮液的光密度对样品路径长度（体积）的依赖性的了解，使得能够生成附着群体（生物膜）的生长曲线。通过这种方式，在生长的各个阶段（0 - 20小时）测定了最低抑菌浓度（MIC），既针对附着在板孔底部生长的细胞，同时也针对在其上方悬浮生长的细胞。杀菌剂包括西曲溴铵、聚六亚甲基双胍、过氧乙酸、苯氧乙醇和氯二甲酚。结果以浮游菌：生物膜MIC比值表示，显示出不仅作为附着和生物膜形成的函数，而且相对于化学试剂的性质也容易发生变化。在某些情况下，附着后立即出现敏感性变化超过两倍的情况，并且在杀菌剂浓度超过MIC时也可能发生。
